The present invention relates to an open-end spinning unit and more particularly to removal of trash within such unit.
In operation of open-end spinning units the initial separation of fibers from a sliver-by an opening roll results in separation of trash which must be removed. This removal of trash has been the subject of concern for those of skill in the art.
Typically, in open-end spinning units such as that disclosed in DE 28 56 028A, sliver is fed between a fiber draw-in roller and a feed plate to an opening roller that separates and combs the fibers and causes trash to separate by centrifugal force and fall by gravity into a trash collection chamber below the opening roller. In this transport, both the fibers and the trash particles are rapidly accelerated to approximately the circumferential speed of the opening roller by rotation of the opening roller and the circulating air flow draft created by the rotation of the roller and the suction induced in the downstream rotor of the spinning unit. Because of the centrifugal force acting upon them, fibers and trash particles, have the tendency to fly off the roller at a tangent when there is no constraining housing adjacent the roller as happens in the region of the outlet opening into the trash collection chamber.
To prevent spinnable fibers from flying away from the opening roller at the trash collection chamber along with the trash particles, an aspiration opening an air inlet is provided in the trash collection chamber for air flow to the opening roller to maintain the fibers, which have a slight mass in proportion to their surface area, firmly against the opening roller in the manner of a pneumatic guide. On the other hand, the trash particles which have a greater mass in proportion to their surface area developed a markedly higher kinetic energy, overcoming this air flow and separated centrifugally from the opening roller to fall into the trash collection chamber.
The trash particles are then subjected to a further air flow for removal through a suction discharge opening. The trash collection chamber may be provided with an air baffle, which is located a slight distance from the trash discharge opening and divides the chamber into a trash separation zone and a trash removal zone. However, this results in only partial separation of the air flows, which are in the same direction, with some fibers remaining in the particle flow and some of the trash particles remaining in the fiber flow.
Since the air baffle is not easily accessible and is therefore difficult to clean, in such an arrangement the disadvantage also exists that deposits of trash particles will occur at the air baffle over time, which has a negative impact on air flow conditions within the spinning unit.
Thus, an important element with a view to satisfactory processing of fiber materials is the separation of the trash at the opening roller housing of a rotor spinning machine. Although the technology of trash separation devices appears relatively simple, these devices are in fact quite problematic and react sensitively to changes. Even slight modifications in trash separation, for instance as a result of trash deposits, can therefore affect the results not only in terms of the quantity of trash removed but can affect the overall outcome of spinning as well.
From German patent DE 42 29 144A1, an open-end spinning unit is also known that substantially comprises a basic housing that accommodates a sliver feed device, an opening roller housing and a rotor housing. This spinning unit has a hinged cover for closing the rotor housing and a conduit plate that has at least a part of a fiber guide conduit and a yarn draw-off conduit. In the region of the basic housing, a trash collection chamber is disposed below the opening roller housing to receive the trash particles combed out of the sliver by the opening roller. The trash chamber is connected to a suction device of the spinning unit itself, via suction connection while the spinning machine itself, via a suction connection. While effective, further increase in the quality of trash separation and removal has been desired.